iio: core: Move the currentmode entry to the opaque structure

This entry should, under no situation, be modified by device
drivers. Now that we have limited its read access to device drivers
really needing it and did so through a dedicated helper, we can
easily move this variable to the opaque structure in order to
prevent any further modification from non-authorized code (out of the
core, basically).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20220207143840.707510-12-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

5 files changed, 18 insertions, 14 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 4706d0e3c954..615662d75e68 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1065,7 +1065,7 @@ static int iio_enable_buffers(struct iio_dev *indio_dev,
 	indio_dev->active_scan_mask = config->scan_mask;
 	indio_dev->scan_timestamp = config->scan_timestamp;
 	indio_dev->scan_bytes = config->scan_bytes;
-	indio_dev->currentmode = config->mode;
+	iio_dev_opaque->currentmode = config->mode;
 
 	iio_update_demux(indio_dev);
 
@@ -1103,7 +1103,7 @@ static int iio_enable_buffers(struct iio_dev *indio_dev,
 		}
 	}
 
-	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+	if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
 		ret = iio_trigger_attach_poll_func(indio_dev->trig,
 						   indio_dev->pollfunc);
 		if (ret)
@@ -1122,7 +1122,7 @@ static int iio_enable_buffers(struct iio_dev *indio_dev,
 	return 0;
 
 err_detach_pollfunc:
-	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+	if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
 		iio_trigger_detach_poll_func(indio_dev->trig,
 					     indio_dev->pollfunc);
 	}
@@ -1135,7 +1135,7 @@ err_run_postdisable:
 	if (indio_dev->setup_ops->postdisable)
 		indio_dev->setup_ops->postdisable(indio_dev);
 err_undo_config:
-	indio_dev->currentmode = INDIO_DIRECT_MODE;
+	iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
 	indio_dev->active_scan_mask = NULL;
 
 	return ret;
@@ -1165,7 +1165,7 @@ static int iio_disable_buffers(struct iio_dev *indio_dev)
 			ret = ret2;
 	}
 
-	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+	if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
 		iio_trigger_detach_poll_func(indio_dev->trig,
 					     indio_dev->pollfunc);
 	}
@@ -1184,7 +1184,7 @@ static int iio_disable_buffers(struct iio_dev *indio_dev)
 
 	iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
 	indio_dev->active_scan_mask = NULL;
-	indio_dev->currentmode = INDIO_DIRECT_MODE;
+	iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
 
 	return ret;
 }
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index fa1e00bee787..a8c4e85c2bb5 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -190,7 +190,9 @@ EXPORT_SYMBOL_GPL(iio_device_id);
  */
 bool iio_buffer_enabled(struct iio_dev *indio_dev)
 {
-	return indio_dev->currentmode
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->currentmode
 		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE |
 		   INDIO_BUFFER_SOFTWARE);
 }
@@ -2072,12 +2074,14 @@ EXPORT_SYMBOL_GPL(iio_device_release_direct_mode);
 
 /**
  * iio_device_get_current_mode() - helper function providing read-only access to
- *				   the @currentmode variable
+ *				   the opaque @currentmode variable
  * @indio_dev:			   IIO device structure for device
  */
 int iio_device_get_current_mode(struct iio_dev *indio_dev)
 {
-	return indio_dev->currentmode;
+	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+	return iio_dev_opaque->currentmode;
 }
 EXPORT_SYMBOL_GPL(iio_device_get_current_mode);
 
diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index f504ed351b3e..585b6cef8fcc 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -444,7 +444,7 @@ static ssize_t iio_trigger_write_current(struct device *dev,
 	int ret;
 
 	mutex_lock(&indio_dev->mlock);
-	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+	if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
 		mutex_unlock(&indio_dev->mlock);
 		return -EBUSY;
 	}
diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
index 2be12b7b5dc5..6b3586b3f952 100644
--- a/include/linux/iio/iio-opaque.h
+++ b/include/linux/iio/iio-opaque.h
@@ -7,6 +7,9 @@
  * struct iio_dev_opaque - industrial I/O device opaque information
  * @indio_dev:			public industrial I/O device information
  * @id:			used to identify device internally
+ * @currentmode:		operating mode currently in use, may be eventually
+ *				checked by device drivers but should be considered
+ *				read-only as this is a core internal bit
  * @driver_module:		used to make it harder to undercut users
  * @info_exist_lock:		lock to prevent use during removal
  * @trig_readonly:		mark the current trigger immutable
@@ -36,6 +39,7 @@
  */
 struct iio_dev_opaque {
 	struct iio_dev			indio_dev;
+	int				currentmode;
 	int				id;
 	struct module			*driver_module;
 	struct mutex			info_exist_lock;
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 31098ffa7dc9..85cb924debd9 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -494,9 +494,6 @@ struct iio_buffer_setup_ops {
  *			also be filed up by the IIO core, as a result of
  *			enabling particular features in the driver
  *			(see iio_triggered_event_setup()).
- * @currentmode:	[INTERN] operating mode currently in use, may be
- *			eventually checked by device drivers but should be
- *			considered read-only as this is a core internal bit
  * @dev:		[DRIVER] device structure, should be assigned a parent
  *			and owner
  * @buffer:		[DRIVER] any buffer present
@@ -523,7 +520,6 @@ struct iio_buffer_setup_ops {
  */
 struct iio_dev {
 	int				modes;
-	int				currentmode;
 	struct device			dev;
 
 	struct iio_buffer		*buffer;